Park brakes (also known as “emergency brakes”) have historically been manually actuated mechanical devices that were configured to pull a cable causing a mechanism to tighten the calipers of the rear brakes of a vehicle. The park brakes have traditionally been used to ensure that a vehicle does not roll out of position, for example, while parked on an incline.
While many vehicles still come equipped with this mechanical device, in recent years, an electronic park brake system has been introduced into the market. The electronic park brake system includes an electronic park brake module (EPBM) and a switch coupled to the EPBM. The switch is mounted in the passenger compartment of the vehicle in a position accessible to the driver or other user. The EPBM is configured to receive an electronic signal when the switch is actuated and in response, the EPBM sends a command to a motor that pulls on a cable which tightens the calipers of the vehicle's rear brakes. In some embodiments, the motor may be mounted directly to the caliper and instead of pulling on a cable, the motor directly tightens the calipers of the rear brakes. When the switch is deactivated, the EPBM sends another signal to the motor to loosen the calipers of the vehicle's rear brakes.
Conventional electronic park brake systems may be configured to function in at least two modes; static mode and dynamic mode. Static mode encompasses the traditional usage described above where the vehicle is parked and the driver/user wants to ensure that the vehicle does not roll away. Dynamic mode encompasses actuation of the vehicle's electronic park brake while the vehicle is in motion. For example, as the vehicle is decelerating to stop for a traffic light or for a stop sign, the driver may wish to engage the electronic park brake instead of using the vehicle's service brake.
When operated in static mode, the EPBM will send a command that causes the motor to exert a higher level of braking force than is applied when the EPBM is operated in dynamic mode. For example, when actuated in static mode, the EPBM may cause the vehicle's park brakes to exert enough braking force to hold the vehicle stationary on a 20% grade.
While the electronic park brake system described above is adequate, there is room for improvement. Conventional electronic park brake systems are easily actuated. For example, a conventional electronic park brake system may be actuated through the pressing of a button mounted to the instrument panel. Such actuation may require very little force and, consequently, it may be possible for the driver or another occupant of the vehicle to unintentionally actuate the system. If this were to happen while the vehicle were traveling at speed, a conventional electronic park brake system would operate in dynamic mode and would exert the predetermined amount of braking force. The sudden onset of the predetermined amount of braking force may be undesirable to the driver when it is not expected.
Accordingly, it is desirable to provide an electronic park brake module that addresses this issue. It is also desirable to provide a system for decelerating a vehicle that addresses this issue. Further, it is desirable to provide a method for decelerating a vehicle that addresses this issue. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.